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Just imagine that any equation is like a balance
x- box with some not known own weight
y- basket with some not known weight

So you are sure that 3 boxes and 4 baskets are exactly 19 kg weight...

Hi,

The problem look like complicated one but it is simple
The idea with Vene diagram is correct and perfect way
Using:

* for union
+ for intersection
/ for subtract

Hi

I believe it is never too early to start with home education.
I have three children, I was talking, telling stories, about anything, especially math related but very simple presented, asking...